Ariston a27 lock out after 20 mins..

[vanga]

My ariston a27 lock out after about 20mins... then after keeps locking out for wvery reset/turn off. If I leave it switched off (at the mains) for a very long time (like a day) I can get to work again for about 20 mins then it locks out again.

I had three engineers come in to have a look and none could figure out what the problem is (i'm also a trainee.. ans this is stumbled me)...

lock out occurs for both HW+CH and HW.

flame ignites and fan starts
flue gas is fine
pressure is ok
pump is ok but measured resisitance 237 ohms

replaced detection electrode and problem persists

Any thoughts - could there be a fault on the PCBs and how would I check that?

 

[Agile]

The lockout on that boiler can I think be triggered by several functions however ignition problems are the most common/likely.

But we dont give advice on gas/combustion aspects on the open forum.

Its difficult to positively identify many PCB faults and many people just replace PCBs when they dont know what the fault is. In most cases its not the PCB and they have overlooked something else.

The Aristons are not one of the easiest boilers to diagnose problems on.

Tony